1. Field of the Invention
This invention relates to shipping containers and more particularly to a one-piece, sift-proof, paperboard liner for use in packaging powdered or semi-liquid material.
2. Description of the Prior Art
A prior art search in the United States Patent and Trademark Office directed to the subject matter of this application disclosed the following United States Letters Pat. Nos. 630,789; 785,102; 1,105,215; 1,168,539; 1,737,319; 1,998,543; 2,070,747; 2,142,342; 2,362,862; 2,412,547; 3,117,711; 3,182,883; 3,285,498; 4,091,984; 4,169,539.
None of the prior art patents uncovered in the search disclosed the specific bellows arrangement for the structure of the bottom portion of the liner as disclosed and claimed in the present invention.